Amodel for my number has 6 ones blocks, 2 hundreds blocks, and 3 tens blocks

Add the fractions and simplify 1/2+ 1/3

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g